Primitive Archer
Main Discussion Area => Bows => Topic started by: radius on July 29, 2009, 10:49:28 pm
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eric krewson's tillering gizmo seems like a failsafe...gets the arc flowing, and leaves the last four inches or so of the tip a little bit stiff. Gotta like it. Thanks for showing me that jig, man!
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Eric's gizmo is one of those things we all speak about..."why didn't I think of that!" ::)
So simple but such a valuable tool. 8)
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it's not perfect though
he admits it won't accurately read the fades...and i find that with my longbow propped to max draw (18" right now) then obviously i can't run the gizmo into the handle area where i want it to equally bend....great for the limbs though!
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Isn't the original gizmo, the walkie talkie by Dean Torges? Just curious.
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Yep it is, just refined a tad. There is another method to look at both fades, and that is to put a block of wood 12" long centered on top of the handle, when you bend the bow on the tree you can watch the gap on both fades. These gadgets are great for starting out, but they don't replace the trained eye.
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It is basically an old bowyers trick. When I started building bows over 20 years ago I read somewhere to use a 6" straight edge rule, held on edge to run out the limb while viewing the space between the ruler and the limb. Wider space meant more bend, narrower space meant less bend. Eric added the pencil(I think) and popularized his idea by spreading the word with pics and instructions or gifts of the gizmo.
I have a gizmo but only use it on complicated staves. For a beginner it makes bow building life a lot easier. Like Dano said, you can't beat a trained eye! That comes from the experience of building lots of bows.
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ok ok, i wasn't trying to give Eric all the credit...but i just made one...i've run that block before too, it's nice to have a pencil in the jig...but you still have to look at the wood.
These yew staves i have are anything but straight and cooperative. when i run the Tiller jig along the limb, i afterwards have to make sure to take wood only from the thicker side of the limb, as they are damn twisted...this one anyway!
i'm just sayin...i like the jig
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It dose work great,I usually only use it till I get it braced,then by eye,also be careful if you are working on a snaky stave or one with humps in the back,if will fool you very easy with these kind of staves.On a clean straight stave you can't beat it.We used them a bunch Sat. with a lot of Hickory staves we were doing for the boy scouts and it really helps.I use what Pat talked about,a straight edge but it is only 3 inches long. :)
Pappy
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i even used a credit card, when i couldn't find anything else ( to check the bend, not to buy a finished bow ;D )
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even used a credit card, when i couldn't find anything else ( to check the bend, not to buy a finished bow )
That's a pretty good idea Marius...I got to give you "credit" for that one! ;D
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I've also built one but when using it i had the following problem: My tiller-radius was progressive/elliptic and I realized that it only works properly in a steady radius - it's always adjusted to a certain radius: so if I went from the wide radius @ the handle towards the tips where the radius gets smaller it wouldn't mark the stiff spots anymore and so delievers wrong results. I think one should always be aware of this.
How do you deal with these circumstances?
Sure I will use it to detect and exactly localize a supposed stiff spot and sure thanks to Eric again!
Cheers
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I does take a little practice. I use it mostly on laminated bows because they are flat. I have found if I mark the bow when drawn to about 18" or so it seems to give me a pretty close tiller. Nothing beats a good eye but some of us just don't have the eye of an artist.
The first couple of times I used it the bows had handshock and I didn't fool with it anymore for a couple of years. I started playing around with what positin the bow was in when I marked it and supplementing with my eye and now I am hooked on it. I used it on the longbow I built for the Hungarian last year and he shot over 450 yard shot with it. Going about 50 yards past the old record.
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Hi Badger, sure interesting when a pro like you swears on it! How do you deal with the radius problem mentioned? When you adjust the gizmo on the wide radius @ the handle it won't detect the stiff spots on the small radius @ the outer limb and when you adjust it to the small radius @ the outer limb it just paints everything on the wide radius near the handle? How do you use it with same adjustment all over the limb, when you have an elliptic tiller? Cheers
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I am always surprised at the trouble people have using the gizmo. I get some mighty fine results from it but it is not my only method of finishing up the tiller. If I have hand shock I know the limbs are slightly out of time and use the shoot and full length scrape method without the gizmo to time the limbs.
I don't worry about the fact that the gizmo won't give you a reading for the fades, I use the board across the bows back to gage this area.
The gizmo isn't the end all be all for bow making but it will give you a valuable head start on going from floor tillering to full brace without any worry about hinging a bow or having one limb significantly stronger than the other. These two things are the major pitfalls for beginning bowyers.
The gizmo will also almost always insure that you will come in over poundage when you have the tiller perfected. This gives you plenty of room to adjust to any tiller configuration you want in your finished bow.
https://www.youtube.com/watch?v=KqvwUqn-EFQ
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Thanks Eric! Got it now after reviewing your vid. One has to adjust the gizmo @ the bendiest spot of the limb and we ar not searching for the weak spots but the stiff ones. ...I always was a bit a hard-to-teach pupil 8) I will try again
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Hi Badger, sure interesting when a pro like you swears on it! How do you deal with the radius problem mentioned? When you adjust the gizmo on the wide radius @ the handle it won't detect the stiff spots on the small radius @ the outer limb and when you adjust it to the small radius @ the outer limb it just paints everything on the wide radius near the handle? How do you use it with same adjustment all over the limb, when you have an elliptic tiller? Cheers
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Later in the process I start working the gizmo out toward the outer limb, I usually leave the last 8" on a bow stiff anyway. I don't think of myself as lowering the weight on a bow as I tiller it anymore. I just keep perfecting the tiller and lowering the weight just happens as a result of that.
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The good thing about it seems to be, that the tilleringprocess follows a strict system or method, not just "scrape a bit here" and" scrape a bit there" - it could make tillering even more relaxing. I will try again ;D
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I am out in the shop today making gizmos to send to Pappy for the guys to use at the Classic next weekend. I send him a few every now and then for the guys to try out.
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I saw the concept overdone in Archery the Technical Side. I say overdone because they used a dial indicator and recorded the bend for lots of positions along the limb.
Eric's pencil marks are all that's needed. I made one with the dial indicator many years ago and used it ONCE. It was more trouble than it was worth.
I don't use a gizmo, because I never have any Osage straight enough to use it!